3D printer spray nozzle structure and method thereof for controlling speed and precision

ABSTRACT

The present invention relates to a technical field of 3D printing, and more particularly to a 3D printer spray nozzle structure and a method thereof for controlling speed and precision. According to the present invention, a feeding pipeline is embedded in an external shell, the feeding pipeline and an extruder are coaxially connected; the extruder is driven by a driving device, so as to rotate relative to the feeding pipeline. A rotation angle of the extruder relative to the feeding pipeline is controlled by rotation of a motor, for controlling a filament area actually sprayed by the extrude, in such a manner that printing speed and precision is controlled for suiting different requirements of different printing area. The present invention controls the printing speed and precision, for improving overall printing speed with precision requirements satisfied, and is applicable to 3D printer spray nozzle structure and controlling.

CROSS REFERENCE OF RELATED APPLICATION

This is a U.S. National Stage under 35 U.S.C 371 of the InternationalApplication PCT/CN2014/082513, filed Jul. 18, 2014, which claimspriority under 35 U.S.C. 119(a-d) to CN 201410331883.4, filed Jul. 11,2014.

BACKGROUND OF THE PRESENT INVENTION

1. Field of Invention

The present invention relates to a technical field of 3D printing, andmore particularly to a 3D printer spray nozzle structure and a methodthereof for controlling speed and precision.

2. Description of Related Arts

3D printing is one of rapid prototyping technologies, which usessoftware for hierarchical discretization of 3D digital models, then usesadhesive materials such as powdered metal or plastic materials, forconstructing an object through stacking layer by layer. 3D printingtechnology belongs to plus manufacturing, which is different from thetraditional minus manufacturing, and is better in saving raw materials.Promoted by manufacturing requirements of personalized and specializedservices, 3D printing has been applied in mold production, personalizedproduct manufacturing, medical, military and other aspects. In the nearfuture, 3D printers will be popular in public families, and service forour life and work.

Common 3D printing technologies comprise fuse deposition technology,which melts filamentous hot-melt materials, and extrudes through a spraynozzle with a micro channel. After being sprayed by the spray nozzle,the filamentous hot-melt materials are deposited on a workbench, and aresolidified when a temperature is lower than a solidifying temperature.Finally a product is formed by stacking the materials. The spray nozzleis a core part, but an inner cross section of an extruder of the spraynozzle of a conventional 3D printer is only circular. In a unit time, afuse volume of the spray nozzle is certain. Due to the inner crosssection of the spray nozzle is not adjustable, printing precision andspeed and the 3D printer are not able to be controlled. However, fordifferent printing purposes and different print areas, differentprinting precision and speed are needed. Even for one model, inner andedge precision requirements are different. Based on the fact that theinner cross section of the spray nozzle of the conventional 3D printeris circular, printing speed and precision are not able to be controlledaccording to different models or different parts of a same model.

SUMMARY OF THE PRESENT INVENTION

A first object of the present invention is to provide a 3D printer spraynozzle whose printing speed and precision are adjustable, aiming at aproblem that internal cross section shapes of conventional 3D printerspray nozzles are all circular, which are not controllable according todifferent models or different parts of a same model.

A second object of the present invention is to provide a method forcontrolling printing speed and precision according to printingrequirements, aiming at a problem that internal cross section shapes ofconventional 3D printer spray nozzles are all circular, which are notcontrollable according to different models or different parts of a samemodel.

Accordingly, in order to accomplish the first object, the presentinvention provides a 3D printer spray nozzle structure, comprising:

a feeding pipeline, and an extruder, wherein the extruder is arrangedunder the feeding pipeline; wherein the extruder is rotatable relativeto the feeding pipeline, so as to adjust a cross section area of asprayed filament.

The 3D printer spray nozzle structure further comprises an externalshell and a driving device, wherein the feeding pipeline is embedded inthe external shell, the feeding pipeline and the extruder are coaxiallyconnected; the extruder is driven by the driving device, so as to rotaterelative to the feeding pipeline.

The driving device comprises a driving gear, a driven gear and a motor;wherein the driving gear is mounted inside the external shell, thedriven gear is mounted on the extruder; the driving gear is engaged withthe driven gear; the motor drives the driving gear; the driven gear isdriven by the driving gear, so as to drive the extruder to rotate.

The driven gear is mounted at a top end of the extruder.

A barycenter of an internal channel cross section shape of the feedingpipeline and a barycenter of an internal channel cross section shape ofthe extruder are at one axle perpendicular to both an internal channelcross section of the feeding pipeline and an internal channel crosssection of the extruder; the extruder is rotatable around the axle.

The internal channel cross section shape of the feeding pipeline and theinternal channel cross section shape of the extruder are both regularpolygons.

The regular polygons comprise triangles and rectangles.

The internal channel cross section shape of the feeding pipeline and theinternal channel cross section shape of the extruder are both thetriangle with a side length of 3a; a rotation angle of the extruderaround the axle perpendicular to both the internal channel cross sectionof the feeding pipeline and the internal channel cross section of theextruder is θ, an area of a coincide region of both the internal channelcross section of the feeding pipeline and the internal channel crosssection of the extruder equals to a cross section area S of materialsactually extruded by the extruder in a unit time; then

${S = {\frac{9\sqrt{3}}{4}\frac{1 + {\tan^{2}\frac{\theta}{2}}}{1 + {\sqrt{3}\mspace{14mu} \tan \mspace{14mu} \frac{\theta}{2}}}a^{2}}},$

wherein a motor-driven rotation angle of the extruder is θ.

The external shell comprises a heater therein, for heating the materialstransported in the feeding pipeline, in such a manner that the materialsare in a melted state; the materials transported are ABS or PLA fusiblematerial.

Accordingly, in order to accomplish the second object, the presentinvention provides a method for controlling printing speed andprecision, wherein:

a method for controlling the printing speed comprises steps of:

defining a printing speed V=K*S*L; wherein S is a cross section area ofa filament actually sprayed by an extruder, L is a unit printing formingarea, K is a printing related constant;

determining a feeding speed by the cross section area S of the filamentactually sprayed by the extruder and the unit printing forming area L,wherein a melting speed is also affected; the feeding speed and themelting speed together determine the printing speed; and

forming a signal referring to changes of S and L for controlling theprinting speed, which also adjusting the feeding speed of a feedingpipeline of a spray nozzle;

wherein a method for controlling the printing precision comprises stepsof: according to different precision requirements, adjusting theprinting speed for controlling printing precision; wherein, when highprinting precision is required, the printing speed is slow; when lowprinting precision is required, the printing speed is high.

A rotation angle of the extruder is adjusted by a motor for changing thecross section area S of the filament actually sprayed by the extruder ina unit time; because a working moving speed of the spray nozzle isconstant, for ensuring Z-axis forming heights of all layers areidentical, the feeding speed of the feeding pipeline is real-timecontrolled according to the cross section area S of the filamentactually sprayed by the extruder; the feeding speed equals in value tothe melting speed of materials transported, and also equals to theprinting speed V during printer working.

When an internal channel cross section shape of the feeding pipeline andan internal channel cross section shape of the extruder are both atriangle with a side length of 3a, the cross section area S of thefilament actually sprayed by the extruder is:

${S = {\frac{9\sqrt{3}}{4}\frac{1 + {\tan^{2}\frac{\theta}{2}}}{1 + {\sqrt{3}\mspace{14mu} \tan \mspace{14mu} \frac{\theta}{2}}}a^{2}}},$

wherein θ is a motor-driven rotation angle of the extruder.

Beneficial Effects:

The present invention controls rotation of the motor for controlling therotation angle of the extruder relative to the feeding pipeline, in sucha manner that the cross section area of the sprayed filament iscontrolled for controlling the printing precision and speed of aprinter. The present invention is able to adjust different printingprecision and speed according to different printing purposes anddifferent printing areas.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring to drawings, the present invention is further illustrated.

FIG. 1 is a front view of a printer spray nozzle according to thepresent invention.

FIG. 2 is a sketch view of main components of the printer spray nozzleaccording to the present invention;

wherein: a-perspective view of a feeding pipeline; b-top view of thefeeding pipeline;

c-perspective view of an extruder; d-top view of the extruder.

FIG. 3 is a top view of an internal channel cross section of the feedingpipeline and an internal channel cross section of the extruder accordingto the present invention, wherein O is barycenters of two identicalequilateral triangles, θ is an angle between perpendicular bisectorsthereof.

FIG. 4 is a top view of the internal channel cross section of thefeeding pipeline and the internal channel cross section of the extruderwhen θ=π/3.

FIG. 5 is a top view of the internal channel cross section of thefeeding pipeline and the internal channel cross section of the extruderwhen θ=0.

FIG. 6 is a logic diagram of factors influencing a printing speedaccording to the present invention.

FIG. 7 is a system diagram of controlling the printing speed accordingto the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 1, a front view of a 3D printer spray nozzle accordingto the present invention is illustrated, wherein main components thereofare illustrated in FIG. 2, comprising a feeding pipeline 103, anextruder 107 and an external shell 101, wherein the feeding pipeline 103and the external shell 101 are mounted on a printer body, the feedingpipeline 103 is embedded in the external shell 101. The external shell101 comprises a heater therein, for heating materials transported in thefeeding pipeline 103, in such a manner that the materials are in amelted state; the materials transported are ABS or PLA fusiblematerials.

The feeding pipeline 103 and the extruder 107 are coaxially connected.An internal channel 102 cross section shape of the feeding pipeline 103and an internal channel 108 cross section shape of the extruder 107 areboth regular polygons, wherein the regular polygons comprise trianglesand rectangles; wherein a barycenter of the internal channel 102 crosssection shape of the feeding pipeline 103 and a barycenter of theinternal channel cross section shape 108 of the extruder 107 are at oneaxle perpendicular to both an internal channel cross section of thefeeding pipeline 103 and an internal channel cross section of theextruder 107.

A driven gear 104 is mounted at a top portion of the extruder 107. Thedriven gear 104 drives the extruder 107 to rotate by rotation. A motorinside the external shell 101 rotates for rotating a main axle 106, anda driving gear 105 is mounted on the main axle 106, which drives adriven gear 104 to rotate. The present invention accurately controls arotation number of the motor through software, so as to control arotation angle θ of the extruder 107 around an axle perpendicular toboth the internal channel 102 cross section of the feeding pipeline 103and the internal channel 108 cross section of the extruder 107.

Referring to FIG. 3, the rotation angle of the extruder 107 around theaxle perpendicular to both the internal channel 102 cross section of thefeeding pipeline 103 and the internal channel 108 cross section of theextruder 107 is θ; wherein a shadowed area is a coincide region of aninternal channel 102 cross section triangle of the feeding pipeline 103and an internal channel 108 cross section triangle of the extruder 107;an area of the coincide region equals to a cross section area of thematerials actually extruded by the extruder 107 in a unit time.

Referring to a preferred embodiment, the present invention is furtherillustrated. The internal channel 102 cross section shape of the feedingpipeline 103 and the internal channel 108 cross section shape of theextruder 107 are both the equilateral triangle with a side length of 3a;the rotation angle of the extruder 107 is θ, the area of the coincideregion of both the internal channel 102 cross section of the feedingpipeline 103 and the internal channel 108 cross section of the extruder107 equals to a shadowed cross section area S of in FIG. 3; then

${S = {\frac{9\sqrt{3}}{4}\frac{1 + {\tan^{2}\frac{\theta}{2}}}{1 + {\sqrt{3}\mspace{14mu} \tan \mspace{14mu} \frac{\theta}{2}}}a^{2}}},$

wherein θ is adjusted by the motor for changing the cross section area Sof the materials actually sprayed by the extruder 107 in a unit time;because a working moving speed of the spray nozzle is constant, forensuring Z-axis forming heights of all layers are identical, the feedingspeed of the feeding pipeline 103 is real-time controlled according tothe cross section area S of the materials actually sprayed by theextruder 107; the feeding speed equals in value to the melting speed ofmaterials transported, and also equals to the printing speed V duringprinter working.

Referring to FIGS. 4 and 7, when the area of the shadowed area issmallest, the printing speed is lowest, which is suitable for conditionswith high printing precision requirement. Referring to FIG. 5, when thearea of the shadowed area is largest, the printing speed is highest,which is suitable for conditions with low printing precisionrequirement, for shortening a printing time. That is to say, accordingto different precision requirements, the printing speed is adjusted forcontrolling printing precision; wherein, when high printing precision isrequired, the printing speed is slow; when low printing precision isrequired, the printing speed is high.

Referring to FIGS. 6 and 7, according to the present invention, a methodfor controlling the printing speed comprises steps of:

defining a printing speed V=K*S*L; wherein S is a cross section area ofa filament actually sprayed by an extruder, L is a unit printing formingarea, K is a printing related constant;

wherein the unit printing forming area is a top surface area formed byextruding the materials along a same direction within a unit time by theextruder 107;

determining a feeding speed by the cross section area S of the filamentactually sprayed by the extruder and the unit printing forming area L,wherein a melting speed is also affected; the feeding speed and themelting speed together determine the printing speed; and

forming a signal referring to changes of S and L for controlling theprinting speed, which also adjusting the feeding speed of a feedingpipeline of a spray nozzle.

1-12. (canceled)
 13. A 3-dimensional printer spray nozzle structure,comprising: a feeding pipeline, and an extruder, wherein the extruder isarranged under the feeding pipeline; wherein the extruder is rotatablerelative to the feeding pipeline, so as to adjust a cross section areaof a sprayed filament.
 14. The 3-dimensional printer spray nozzlestructure, as recited in claim 13, further comprising: an external shelland a driving device, wherein the feeding pipeline is embedded in theexternal shell, the feeding pipeline and the extruder are coaxiallyconnected; the extruder is driven by the driving device, so as to rotaterelative to the feeding pipeline.
 15. The 3-dimensional printer spraynozzle structure, as recited in claim 14, wherein the driving devicecomprises a driving gear, a driven gear and a motor; wherein the drivinggear is mounted inside the external shell, the driven gear is mounted onthe extruder; the driving gear is engaged with the driven gear; themotor drives the driving gear; the driven gear is driven by the drivinggear, so as to drive the extruder to rotate.
 16. The 3-dimensionalprinter spray nozzle structure, as recited in claim 15, wherein thedriven gear is mounted at a top end of the extruder.
 17. The3-dimensional printer spray nozzle structure, as recited in claim 14,wherein a barycenter of an internal channel cross section shape of thefeeding pipeline and a barycenter of an internal channel cross sectionshape of the extruder are at one axle perpendicular to both an internalchannel cross section of the feeding pipeline and an internal channelcross section of the extruder; the extruder is rotatable around theaxle.
 18. The 3-dimensional printer spray nozzle structure, as recitedin claim 15, wherein a barycenter of an internal channel cross sectionshape of the feeding pipeline and a barycenter of an internal channelcross section shape of the extruder are at one axle perpendicular toboth an internal channel cross section of the feeding pipeline and aninternal channel cross section of the extruder; the extruder isrotatable around the axle.
 19. The 3-dimensional printer spray nozzlestructure, as recited in claim 16, wherein a barycenter of an internalchannel cross section shape of the feeding pipeline and a barycenter ofan internal channel cross section shape of the extruder are at one axleperpendicular to both an internal channel cross section of the feedingpipeline and an internal channel cross section of the extruder; theextruder is rotatable around the axle.
 20. The 3-dimensional printerspray nozzle structure, as recited in claim 17, wherein the internalchannel cross section shape of the feeding pipeline and the internalchannel cross section shape of the extruder are both regular polygons.21. The 3-dimensional printer spray nozzle structure, as recited inclaim 18, wherein the internal channel cross section shape of thefeeding pipeline and the internal channel cross section shape of theextruder are both regular polygons.
 22. The 3-dimensional printer spraynozzle structure, as recited in claim 19, wherein the internal channelcross section shape of the feeding pipeline and the internal channelcross section shape of the extruder are both regular polygons.
 23. The3-dimensional printer spray nozzle structure, as recited in claim 20,wherein the regular polygons comprise triangles and rectangles.
 24. The3-dimensional printer spray nozzle structure, as recited in claim 22,wherein the regular polygons comprise triangles and rectangles.
 25. The3-dimensional printer spray nozzle structure, as recited in claim 23,wherein the internal channel cross section shape of the feeding pipelineand the internal channel cross section shape of the extruder are boththe triangle with a side length of 3a; a rotation angle of the extruderaround the axle perpendicular to both the internal channel cross sectionof the feeding pipeline and the internal channel cross section of theextruder is θ, an area of a coincide region of both the internal channelcross section of the feeding pipeline and the internal channel crosssection of the extruder equals to a cross section area S of materialsactually extruded by the extruder in a unit time; then$S = {\frac{9\sqrt{3}}{4}\frac{1 + {\tan^{2}\frac{\theta}{2}}}{1 + {\sqrt{3}\mspace{14mu} \tan \mspace{14mu} \frac{\theta}{2}}}a^{2}}$wherein a motor-driven rotation angle of the extruder is θ.
 26. The3-dimensional printer spray nozzle structure, as recited in claim 24,wherein the internal channel cross section shape of the feeding pipelineand the internal channel cross section shape of the extruder are boththe triangle with a side length of 3a; a rotation angle of the extruderaround the axle perpendicular to both the internal channel cross sectionof the feeding pipeline and the internal channel cross section of theextruder is θ, an area of a coincide region of both the internal channelcross section of the feeding pipeline and the internal channel crosssection of the extruder equals to a cross section area S of materialsactually extruded by the extruder in a unit time; then$S = {\frac{9\sqrt{3}}{4}\frac{1 + {\tan^{2}\frac{\theta}{2}}}{1 + {\sqrt{3}\mspace{14mu} \tan \mspace{14mu} \frac{\theta}{2}}}a^{2}}$wherein a motor-driven rotation angle of the extruder is θ.
 27. The3-dimensional printer spray nozzle structure, as recited in claim 25,wherein the external shell comprises a heater therein, for heating thematerials transported in the feeding pipeline, in such a manner that thematerials are in a melted state; the materials transported are ABS orPLA fusible materials.
 28. The 3-dimensional printer spray nozzlestructure, as recited in claim 26, wherein the external shell comprisesa heater therein, for heating the materials transported in the feedingpipeline, in such a manner that the materials are in a melted state; thematerials transported are ABS or PLA fusible materials.
 29. A method forcontrolling speed and precision of a 3D printer spray nozzle structure,wherein: a method for controlling the printing speed comprises steps of:defining a printing speed V=K*S*L; wherein S is a cross section area ofa filament actually sprayed by an extruder, L is a unit printing formingarea, K is a printing related constant; determining a feeding speed bythe cross section area S of the filament actually sprayed by theextruder and the unit printing forming area L, wherein a melting speedis also affected; the feeding speed and the melting speed togetherdetermine the printing speed; and forming a signal referring to changesof S and L for controlling the printing speed, which also adjusting thefeeding speed of a feeding pipeline of a spray nozzle; wherein a methodfor controlling the printing precision comprises steps of: according todifferent precision requirements, adjusting the printing speed forcontrolling printing precision; wherein, when high printing precision isrequired, the printing speed is slow; when low printing precision isrequired, the printing speed is high.
 30. The method, as recited inclaim 29, wherein a rotation angle of the extruder is adjusted by amotor for changing the cross section area S of the filament actuallysprayed by the extruder in a unit time; because a working moving speedof the spray nozzle is constant, for ensuring Z-axis forming heights ofall layers are identical, the feeding speed of the feeding pipeline isreal-time controlled according to the cross section area S of thefilament actually sprayed by the extruder; the feeding speed equals invalue to the melting speed of materials transported, and also equals tothe printing speed V during printer working.
 31. The method, as recitedin claim 29, wherein when an internal channel cross section shape of thefeeding pipeline and an internal channel cross section shape of theextruder are both a triangle with a side length of 3a, the cross sectionarea S of the filament actually sprayed by the extruder is:$S = {\frac{9\sqrt{3}}{4}\frac{1 + {\tan^{2}\frac{\theta}{2}}}{1 + {\sqrt{3}\mspace{14mu} \tan \mspace{14mu} \frac{\theta}{2}}}a^{2}}$wherein θ is a motor-driven rotation angle of the extruder.
 32. Themethod, as recited in claim 30, wherein when an internal channel crosssection shape of the feeding pipeline and an internal channel crosssection shape of the extruder are both a triangle with a side length of3a, the cross section area S of the filament actually sprayed by theextruder is:$S = {\frac{9\sqrt{3}}{4}\frac{1 + {\tan^{2}\frac{\theta}{2}}}{1 + {\sqrt{3}\mspace{14mu} \tan \mspace{14mu} \frac{\theta}{2}}}a^{2}}$wherein θ is a motor-driven rotation angle of the extruder.